As a matter of fact, no one denies that life has had a beginning on our globe. The physicist teaches that a beginning of our entire solar system is implied in the law of the degradation of energy, and various attempts have been made to determine the time of this beginning. The older calculations were based on the rate of solar radiation; the more recent ones, however, are based on quantitative estimates of the disintegration products of radioactive elements. Similarly, the geologist and the astronomer propound theories of a gradual constitution of the cosmic environment, which organic life requires for its support, and all such theories imply a _de novo_ origin or beginning of life in the universe. Thus the old _nebular hypothesis_ of Laplace postulated a hot origin of our solar system incompatible with the coëxistence of organic life, which, as the experiments of Pasteur and others have shown, is destroyed, in all cases, at a temperature just above 45° Centigrade (113° Fahrenheit). Even the enzymes or organic catalysts, which are essential for bio-chemical processes, are destroyed at a temperature between 60° and 70° Centigrade. This excludes the possibility of the contemporaneousness of protoplasm and inorganic matter, and points to a beginning of life in our solar system. Moreover, independently of this theory, the geologist sees in the primitive crystalline rocks (granites, diorites, basalts, etc.) and in the extant magmas of volcanoes evidences of an azoic age, during which temperatures incompatible with the survival of even the blue-green algæ or the most resistent bacterial spores must have prevailed over the surface of the globe. In fact, it is generally recognized by geologists that the igneous or pyrogenic rocks, which contain no fossils, preceded the sedimentary or fossiliferous rocks. The new _planetesimal hypothesis_, it is true, is said to be compatible with a cold origin of the universe. Nevertheless, this theory assumes a very gradual condensation of our cosmos out of dispersed gases and star dust, whereas life demands as the _sine qua non_ condition of its existence a differentiated environment consisting of a lithosphere, a hydrosphere, and an atmosphere. Hence, it is clear that life did not originate until such an appropriate environment was an accomplished fact. All theories of cosmogony, therefore, point to a beginning of life subsequent to the constitution of the inorganic world.